This commit makes the library define the |PEG| global variable (for
browser export) and possibly assign it into |module.exports| (for
Node.js export) later. The |module.exports| assignment is done *outside*
the main library |function| statement.
The big idea behind this is to make copy & paste inclusion of the
library into another code easier -- one just needs to strip the last
three lines.
The source code is now in the src directory. The library needs to be
built using "rake", which creates the lib/peg.js file by combining the
source files.